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hey guys!
i'm new here and i'm new in the world of MODBUS. so last few days i read a lot about MODBUS and stuff. i created a connection between two windows PCs and made MODBUS run and had a look with wireshark.
so finally i saw the function codes and searched for on the internet. that's how i found different explanations and your forum. unfortunately i can't find that thread again. but anyway, in the thread a newbee asked something and then one of your experienced users explained the function codes. and he says that coils inputs etc are addresses.
anyway. the information i got from that thread was:
Read Coil
(read/write Boolean)
Read Discrete Inputs
(read only)
Read Holding Registers
(read/write)
Read Input Registers
(read only)
so he said. read coil and read input registers are functions that can read AND write...
in this page
http://www.simplymodbus.ca/faq.htm#FC
i find for function code 1-4 that the action IS reading nothing else... so i don't know whats right and whats wrong. i would be very thankful if someone can explain me the 8 codes with a few words or send me a link where i can get those information for myself and be 100% sure its right.
i think this one is different too
http://www.modbustools.com/modbus.asp
well, maybe i'm too confused. please excuse me and my bad english, but i am new in this topic and just want to know how its right. i got tons of more questions but i think this is enough for the beginning. hope u answer me
i'm new here and i'm new in the world of MODBUS. so last few days i read a lot about MODBUS and stuff. i created a connection between two windows PCs and made MODBUS run and had a look with wireshark.
so finally i saw the function codes and searched for on the internet. that's how i found different explanations and your forum. unfortunately i can't find that thread again. but anyway, in the thread a newbee asked something and then one of your experienced users explained the function codes. and he says that coils inputs etc are addresses.
anyway. the information i got from that thread was:
Read Coil
(read/write Boolean)
Read Discrete Inputs
(read only)
Read Holding Registers
(read/write)
Read Input Registers
(read only)
so he said. read coil and read input registers are functions that can read AND write...
in this page
http://www.simplymodbus.ca/faq.htm#FC
i find for function code 1-4 that the action IS reading nothing else... so i don't know whats right and whats wrong. i would be very thankful if someone can explain me the 8 codes with a few words or send me a link where i can get those information for myself and be 100% sure its right.
i think this one is different too
http://www.modbustools.com/modbus.asp
well, maybe i'm too confused. please excuse me and my bad english, but i am new in this topic and just want to know how its right. i got tons of more questions but i think this is enough for the beginning. hope u answer me
